Power plant



April 1941 i H. w. CASEY 2,240,011

rowEn PLANT Filed Oct. 26, 939

Patented Apr. 29,1941

POWER PLANT Hilton W. Casey, Boothwyn, Pat, asslgnor of fiftyone-hundredth: to

Edward Margolin, and

twenty one-hundredth: to Aaron Tollimboth 01 Chester, Pa.

Application October 26, less, Serial at. 301,505 2 Claims. (or. co -5s)This invention relates to power plants of the type comprising aninternalcombustion engine as a power unit 'and a hydraulic systemthrough which the engine power is transmitted to the part or partsto'bedriven.

Generally speaking, the primary object of the invention is to provide. ahydraulic power transmitting system to adapt internal combustion enginesof the Diesel type for the operation oi motor vehicles.

Motor vehicles must be capable of being started either slowly or quicklyand operated at extremely high and extremely low speeds and of havingtheir speeds suddenly accelerated and decelerated. Accordingly, thepower plant of a motor vehicle must be quite flexible in its operation.Gasoline engines are quite flexible in operation and therefore are wellsuited for the operation of motor vehicles, but gasoline engines do notpassees the efliciency of engines of the Diesel type. On the other hand,engines of the Diesel type do not possess the flexibility in operationof engines of the gasoline type. In other words, engines of form of aDiesel engine, 0 designates, generally,

a pump of any suitable type connected in any the Diesel'type areincapable of being operated at the extremely high and the extremely lowspeeds of gasoline engines and of having their speeds suddenly variedand, therefore, are incapable of being successfully used in the samemanner as gasoline engines for the operation of motor vehicles. Yet, forthe sake of economy in operation and for various other reasons it isvery desirable to employ Diesel engines for the operation of motorvehicles. Accordingly, the primary object of the invention, moreparticularly stated, is to provide a hydraulic system to permit the useof Diesel engines as the power plants of motor vehicles and, at the sametime, to afford even greater flexibility in the operation of thevehicles than is afl'orded by gasoline engineswhich transmit their powerthrough the usual, well known mechanical transmission gear systems. V 1H! i Another object of the invention is to provide a hydraulic powertransmission system as stated which is simple and inexpensive, easilyinstalled in motor vehicles and thoroughly reliable and emcient inoperation. r

, With the foregoing and other objects in view, which will become morefully apparent as the nature of the invention is better understood, thesame'consists in the novel combination and arrangement of elements aswill be hereinafter more fully described, illustrated in theaccompanying drawing and defined in the appended claims.

suitable manner with the engine B to be driven by said engine, and Ddesignates, generally, a reversible motor of any suitable type to bedriven by liq d under pressure and operatively connected any suitablemanner with the wheels of the vehicle A to drive said wheels and therebydrive the vehicle.

Associated with the pump 0 and the motor D is an expansible andcontractible high pressure liquid chamber a and an expansible and contractible liquid reservoir chamber 2).

In the present instance the chambers a and b are comprised by cylindersid and ii, respectiyely, each closed at least at one endand havingtherein fluid-tightly slidable pistons 12 and i3, respectively, thechamber a being comprised by the part of the cylinder it between oneclosed end thereof and its related piston i2, and the chamber b beingcomprised by the part of the cylinder l I between one closed end thereofand therelated piston H3. The other ends of the cylinders it and it maybe open or closed as desired. In any event, said cylinders id and .iiare provided at their said other ends or at other suitable points thechamber a. by a pipe 58 having interposed therein a check valve i 9which opens toward said chamber a whereby fluid deliveredby the pump 0is free to enter the chamber a, but is prevented from returning to thepump from said chamber through said pipe 88.

The motor D has two ports 20 and 2! through which liquid may becirculatedin either direction through the motor to operate the same ineither direction. In this connection it may be assumed in the presentinstance that liquid supplied to the motor D through the port Eli andexhausted therefrom through the port 2i effects operation of said motorin a direction to impart forward motion to the vehicle A, and thatliquid supplied to said motor through the port 2i and exhaustedtherefrom through the port 20 efiects operation of said motor in adirection to impart reverse or backward movement to the vehicle A.

The ports 2t and 2t are connected with the pipe i8 and, consequently,with the pump C and the chamber a by pipes 22 and 28, respectively; theinlet of the pump C is connected with the pipe is by a pipe '24; thepipe 22 is connected with the pipe 24 by a pipe 25, and the pipe 23 isconnected with the pipe 25 by a pipe 26 a branch 2'5 of which isconnected with the chamber b.

At the junction of the pipeszi and 25 is a throttle valve 26 of anysuitable type which is 2 manually operable by any suitable means, such 4as a foot pedal or hand lever as indicated at "29, V to establishcommunication between the outlet of the pump (3 and the port 2@ of themotor D through the pipes to and 22 while simultaneously 2 denyingcommunication between the pipe 22 and the inlet of the pump through thepipe 2a, or to establish communication between port it! of the motor Dand the inlet of the pump C through the pipes 22 and 25 whilesimultaneously denying communication between the outlet of the pump (2and said motor port 2d.

At the Junction of the pipes 23 and 2a is a, throttle valve to of anysuitable type which is manually operable'by any suitable means, such 3as a foot pedal or hand lever as indicated at 36, to establishcommunication between the port 20 of the motor D and the inlet of thepump C through the said pipes 23 and 26 while simuitaneously denyingcommunication between the pipe 4 i8 and the said motor port 211, or toestablish communication between the pipe ill and thespid motor port 29.through the pipe 23 while simultaneously denyingcommunication betweensaid pipe 23 and the pipe 26.

The check valve i9 is arranged in the pipe it 4 between the pointsoflconnection with-said pipe B8 of the pipes 22 and2d. Another checkvalve 32 is arranged in the pipe 25 and opens toward the pipe 24, andanother check valve 38 is arranged in the pipe 28 and also opens towardthe pipe 24.

In the pipe 24 is a valve 34 which is operable to establish and to denycommunication through said pipe 24 betweenothe pipe t8 and the inletofthe pump C. Normally this valve 34 has a p sition denying.communication between the pipe 18 and the pump inlet, but there is asuitable connection 35 between said valve and the chamber a whereby saidvalve is actuated to establish communication between the pipe 18 and thepump inlet in response to the pressure in said chamber a rising to orexceeding a predetermined value. 1

In the connection 35 there preferably is provided a suitable yleldablemeans, indicated conventionally and designated as 36 to insure a gradualactuation of the valve 34 by rise 'of pressure in the chamber a to apredetermined value. Preferably, too, there is provided a suitable Imeans, such as a hand lever or foot pedal 31 operatively connected withthe valve." whereby ;said valve may be actuated manually to establishcommunication through the pipe between Inthe connections between thehand levers or mam respectively, preferably are provided suitable footpedals 29 and 3| and the valves 28 and 30,

yieldable means, indicated conventionally and designated as 38, toinsure gradual actuation of said valves 28 and 30 by said hand. leversor foot pedals.

. The valves'td and 36 not only are operable to the two positionsheretofore stated, but to intermediate positions in which ,they normallyare disposed and in which theyrespectively deny any communicationtherethrough between the pipes which they control.

The spring 96 is sufiiciently strong so that, when compressed, it actsthrough the piston E2 to impose on liquid contained in the chamber a apressure sufilciently high to cause the liquid,

when supplied from said chamber to the motor D, to operate said motor tomove the vehicle. On the other hand, the spring ll is comparativelyweak, being only sumciently strong to maintain the system filled withliquid from the reservoir chamber to.

' The operation of the system, assuming to begin with that the vehicleis at rest, that the valves 2d and lit are in their normal positionsdenying communication therethrough between the pipes which they control,that the chamber a is contracted and that the chamber b is expanded andcontains a reserve oi liquid, is as follows:

The valve to is manually actuated to establish communication between thepump outlet and inlet through the pipes l8 and 24 so that the liquid inthe system is circulated only through the pump, thereby to permit thepump to operate without developing pressure and to enable easierstarting of the engine B than would be possible if the pump, uponinitiation of operation 5 thereof, immediately began to developpressure.

The engine B then is started. The valve 34 then is returned to itsnormalposition denying communication between the pipe l8 and the pump inletthrough the pipe 24 and the engine is brought up to a speed such that itoperates the pump '0 to deliver liquid through the pipe IE to thechamber a at a desired operating pressure at least as great as thepressure which is exerted by the spring to when said spring iscompressed. When this engine speed is attained it may be assumed thatthereafter the engine is I operated constantly at such speed. Operationof the pump 0 resultsin liquid being delivered through the pipe iii tothe chamber a and in expansion of said chamber against the force ofthe-spring l6, liquid to compensate for the llqllld delivered to thechamber a flowing to the low pressure side of the pump 0 from thechamber b through the pipes 21 and 24. Upon filling of the chamber awith liquid, continued operation of the pump results in an increase inpressure in said chamber and in consequent operation of the connection35 to open thevalve 34.

Thereafter, and until the valves 28 and30 are I actuated, the liquidcirculates in a closed circuit.

through the pipes 18 and 24 and the valve 34, and the chamber a ismaintained filled with liquid under a pressure equivalent to the forceexerted by the spring l6. If, then, the valve 28 is actuated toestablish communication of the delive y side of the pump C and thechamber a with the port 22 01 the motor D, and the valve 30 is actuatedto establish communication between the pipes '23 and 26, as illustratedin Fig. 1 of the drawing, liquid is delivered from the chamber a a andthe pump 0 through the pipes l8 and 22 and valve "to the port 20 of themotor D and flows from the port 2| of said motor through theplpe 23, thevalve 30 and the pipes 26 and 24 to the pump 0. The motor D thereby isoperated in a direction to impart forward motion to the vehicle. If, onthe other hand, the valve 28 is actuated to cut off communicationbetween the pipe l8 and the port 20 of the motor D and to establishcommunication between said port at and the inlet of the pump C throughthe pipes 22, 25 and 24, and if the valve 30 is actuated to cut oifcommunication between the pipes 23 and 2t and to establish communicationbetween the pipes l8 and 23, ,liquid is delivered from, the chamber aand the pump C through the pipes i8 and 23 to the port 2! of the motorD, and flows from the port 20 of said motor through the pipe 22, thevalve 28 and the pipes 25 and it to the inlet of the pump C. The motor Dthereby is operated in a direction to impart reverse or backwardmovement to the vehicle. In either case, the amount of opening of thevalves 28 and 30 determines, of course, the speed at which the vehiclewill be moved. As liquid flows from the chamber a to the motor D, thepump C supplies liquid to said chamber a, thereby maintaining acirculation of liquid through themotor D and maintaining said motor inoperation. In this connection it will be apparent that, due totheexpansible chamber a, smooth starting of the vehicle is assuredwithout recourse to change in speed of the engine B. Also, it will beapparent that, due to the chamber a, subsequent smooth v operation ofthe vehicle will be assured despite slight variations in resistance tomovement of the vehicle, because the chamber or acts expansively toabsorb excess pressure developed by the pump Bwhen a high pressure isnot required for operation of the vehicle, and contractively to lurnishpressure for operation of the vehicle in any instance where the pressuredeveloped by the pump is momentarily insufilcient. In other words, thechamber a acts to compensate for fluctuations in pressure in the systemand to maintain a substantially uniform operating presaasqon I claim:

l. A power plant comprising a power unit, a liquid pump connected withsaid power unit to be driven thereby, a liquid motor operativelyconnected with an element to be driven, said motor being reversible andhaving a pair of ports either for the inlet of liquid and the other forthe outlet of liquid, an expansible and contractible chamber, yieldablemeans tending constantly to contract said chamber, pipe means connectingthe. outlet of said pump with said chamber and with both of the-ports oisaid motor, pipe means connecting the ,inlet of said pump with both orthe ports of said motor and also with the outlet of said pump, valves insaid pipe means for directing liquid from the output of the pump toeither of the ports of said motor and irom the other port of said motorto the inlet of said pump,

an expansible and contraotible liquid reservoir,

means tending constantly to contract said reservoir, a connectionbetween said reservoir and the inlet of the pump, valve means forplacing the outlet of the pump in direct communication with the inletthereof and also for denying direct communication between the outlet andthe inlet of the pump so as to require liquid supplied by thepump toflow to said chamber and said motor, manual means for actuating saidlast,

' for the inlet of liquid and the other for the outsure in the systemunder all ordinary conditions of operation of the vehicle at any givenspeed; also, to aiiord a reserve of liquid under pressure for vehiclestarting and equivalent purposes. Of course, the speed of the engine Bmay be varied to vary the speed of the vehicle, but due to the chamber athe speed of the vehicle may be suddenly increased and decreased withoutchanging the speed of the engine B. It will thus .be' apparent that theengine B may be of the Diesel type operating at constant speed under anygiven operating condition of the vehicle.

When the chamber it acts contractively to supply liquid to the motor D,liquid flows through the pipe 2i to the chamber b in an amountcorresponding'to the amount discharged from the chamber a, and when,subsequently, the chemher a again becomes filled with liquid, the springlet of said liquid so that the motor maybe operated in either directiondepending upon the direction of flow of the liquid supplied thereto, anexpansible and contractible chamber, yieldable means tending constantlyto contract said chamber, a pipe connecting the outlet of said pump withsaid chamber, a first branch pipe connecting said first pipe with one ofthe ports of said motor, a second branch pipe connecting said firstmentioned pipe to the other of the ports of said motor, a third branchpipe connecting said firstmentioned pipe with the inlet of said pump, afirst by-pass pipe connecting said first branch pipe with said thirdbranch pipe, a second bypass'pipe connecting said second branch pipewith said third branch pipe, a valve at the junc tion of saidfirstbranch pipe and said first bypass pipe operable to, place saidfirst branch pipe in communication with said first by-pass pipe andsimultaneously to deny communication between said first mentioned'pipeand the motor through said first branch pipe, said valve also beingoperable to establish communication between, said first mentioned pipeand the motor through said first branch pipe and to simultastructionmay'be resorted to, without departing from the spirit of the inventionand scope of appended claims.

the

neously deny communication between said first branch pipe and said firstby-pass pipe, a second valve at the Junction of said second branch pipeand said second by-pass pipe operable to place said first mentioned pipein communication with the motor through said second branch pipe and tosimultaneously deny communication between said second branch pipe andsaid second by-pass pipe, said second valve also being operable to placesaid second branch pipe in communication with said second by-pass pipeand to simultaneously deny communication between said first mentionedpipe and the motor through said second branch pipe, 9. third valve in.said third branch pipe operable to deny and also to establishcommunication between said first mentioned pipe and the inlet of thepump through said third branch pipe, means for manually operating saidthird valve, means operable in response to rise of the pressure in saidchamber to a predetermined value to actuate said third 10 valve toestablish communication between said first mentioned pipe and the inletof the pump through said third branch pipe, a liquid reservoir connectedwith said first by-pass pipe, a check valve in each by-pass pipe openingtoward said third branch pipe, and a check valve in said first mentionedpipe, between the connections of said by-pass pipes therewith, openingtoward said chamber. I

HILTON W. CASEY.

